Goods that cannot withstand autoclaving temperatures can be sterilized with sterilizers using a biocidal gas such as ethylene oxide. Ethylene oxide sterilizers have a sterilizing chamber where the goods to be sterilized can be placed. The door of the sterilizing chamber can then be sealed, and the operator can initiate a sterilizing cycle. For ethylene oxide to exert maximum effect, the goods can be pre-treated with the proper amount of humidity; to achieve this, a vacuum (e.g., partial vacuum) can be drawn within the sterilizing chamber and then water can be released into the chamber. When the correct amount of humidification has been achieved within the chamber, an appropriate charge of ethylene oxide gas can be released and allowed to act on the surfaces and be absorbed by the goods for a period of time. Once the goods are sterile, the ethylene oxide gas can be purged from the chamber and the goods, and the chamber door can be released so the goods can be unloaded.
It can be desirable to achieve the proper humidification within the chamber, i.e., prior to releasing the ethylene oxide gas, at a relatively quick rate, ideally without over-humidifying the chamber, which may require premature chamber evacuation and/or disrupt an entire sterilization cycle.